Can You Drink Protein Shakes During Intermittent Fasting?

intermittent fasting protein shake

Intermittent fasting may be one more step in your quest for peak fitness — a pursuit that means you need to eat well and work out hard. If you exercise and practice intermittent fasting, protein shakes may be a vital part of your routine. And you may be wondering, “Can I still drink whey protein while I’m on intermittent fasting?” If you’re not a whey protein fan, you might be curious about protein from other sources as well.

The short answer is yes — if you drink it during your eating window. But do you really need to drink protein shakes if you participate in intermittent fasting? Because there are far better ways to get more protein.

Do Protein Shakes Break Your Fast?

You can have protein shakes while you are on intermittent fasting, but if you drink one outside of your eating window, it will break your fast. Protein shakes is a caloric beverage, and if you eat or drink anything containing calories, you are, by definition, no longer fasting. So, save it for your eating window.

can i drink whey protein while intermittent fasting

Protein Shakes During Your Eating Window

If you’re on intermittent fasting, you should look at your protein shake like you would any other food or beverage — save it for your eating window. But during that window consume it however you typically would.

Unfortunately, if you work out in a fasted state, you might not be able to drink your shake after you exercise. The jury is still out on which is more important — getting a protein hit right after your workout, or your overall protein consumption for the day. If you want to do both (exercise while fasted and have your post-workout shake), you’ll need to workout near the end of your fasting period. It’s important to make sure you are on the right fasting plan that suits your needs. Take our quiz and be 100% sure your intermittent fasting plan is the one for you.

Is Protein Crucial for Weight Loss?

If you’re fasting for weight loss, protein is vital. Your body digests protein more slowly than carbs, that’s why protein can help you feel satiated longer. And protein changes the levels of hormones that control your appetite. Protein reduces your production of ghrelin — the hormone which tells your brain you’re hungry. It also increases the levels of hormones that tell your mind you’re full. 

This hormonal release means if you consume more protein, it can naturally help you eat less without feeling hungry. But don’t overdo it. Your body will break excess protein into sugars through a process called gluconeogenesis, which causes your body to release insulin and signals it to store fat, defeating your weight loss effort.

How Much Protein Does Your Body Need?

best protein shake for intermittent fasting

You might be surprised. While conventional wisdom suggests that you might need to eat a steak at every meal if you’re working out, the average person only needs 0.8 grams of pure protein per kilogram of body mass per day.

Do You Need a Protein Shake?

Protein shakes are convenient but may not be the best way to add this macronutrient to your meals. Most protein shakes are packed with artificial sweeteners, are high in calories and low in other nutrients, and they often contain a low-quality “whey isolate.” If you’re fasting for better health, then you may want to add high-protein foods to your eating plan instead.

Good sources of protein include most animal products (including milk and eggs), legumes, tofu, and nut butter. Beans and whole grain rice together form a complete protein as well.

There’s no reason you can’t enjoy a protein shake while you’re intermittent fasting. Be sure to drink it during your standard eating window and try not to think of your protein shake as a beverage. Like any other caloric beverage, a protein shake will break your fast and might undo your efforts.

It’s okay if you prefer protein shakes as a supplement to your daily protein intake. Be sure you read labels and choose a brand with high-quality ingredients and no added sweeteners. If you’re neglecting other dietary sources of protein in favor of protein shakes, consider adding some high-protein foods in place of your daily shake.

Author's bio


Linda Endicott

Linda is an experienced health and wellness writer, a proponent of intermittent fasting. For several years, Linda focused her writer on diabetes and nutrition, and she joined the Simple team to contribute to spreading knowledge about healthy eating habits.